A mobile device may operate as a digital walkie-talkie over Internet Protocol (IP). The digital walkie-talkie over IP may operate on the basis of a half duplex communication system where, although two-way communication may be performed, only one party may send a signal at a time. Once a party begins receiving a signal, it must wait for the transmitter to stop transmitting before replying. A half duplex communication is multicast over a communication network so that one party may transmit the same signal to a plurality of recipients. For example, an audio signal being sent over a particular channel may be multicast to any individual who is tuned into that channel.
A full duplex system utilizing a communication that is unicast includes certain advantages such as identification protocols so a receiving user may know the identity of the sending user. The half duplex system that multicasts a communication does not include these advantageous features. Thus, there is a need to incorporate the features of a unicast call into a multicast call.